Plastic containers adapted for stacking



Feb. 14, 1967 G. K. PARKER ETAL. 3,303,965

PLASTIC CONTAINERS ADAPTED FOR STACKING Filed Jan. 15, 1965 3 sheetssheet 1 .ZVVEA/TOES.

050265 E. PAQKEQ 6252440 M555 Feb. 14, 1967 PARKER ETAL.

PLASTIC CONTAINERS ADAPTED FOR STACKING 5 Sheets-Sheet 2 Filed Jan. 15, 1965 KE NMN %P. M W Z 9 2 5 G Feb. 14, 1967 e. K. PARKER ETAL PLASTIC CONTAINERS ADAPTED FOR STACKING 3 Sheets-Sheet 3 Filed Jan. 13, 1965 [A/vEA/roes GEORGE E. PA QKEQ 052040 71/: M595 a/45 44W flrrapA/gxs.

United States Patent 3,303 965 PLASTIC CONTAINERS AII'APTED FOR STACKIN George K. Parker, Woodside, and Gerald W. Neese, Compton, Califi, assignors to Purex Corporation, Ltd., Lakewood, Califl, a corporation of California Filed Jan. 13, 1965, Ser. No. 425,691 7 Claims. (Cl. 220-97) This invention has to do generally with plastic loadcarrying containers adapted for stacking in vertical alinement, and has for its general object to provide such containers with novel configurations adapting them to thermoforrning from essentially sheet plastic stock with shape features and characteristics affording to the containers superior strength in support of stacked loads, in relation to minimal required wall thicknesses of the containers.

As a typical adaptation, the invention finds embodiment in open top cases adapted to contain and carry four gallon-size liquid-containing bottles, with particular attention being given the shape characteristics of the cases permitting them to support without impairment the considerable loads imposed by vertical stacking of the filled cases. Illustratively, and for the typical purpose indicated, the invention will be described with reference to stackable cases of essentially polygonal, and specifically of essentially square horizontal cross sectional shape, adapted to receive four gallon-size bottles or like containers.

As to structural features, the invention contemplates formation of the plastic case with downward and out-ward angularity to be compatible with the later described stacking relation of the cases, and formation of each case at its corners with vertical rib configurations so positioned and related as to be capable of supporting the bulk if not the entirety of vertical stack loadings, thus relieving the sides of the case between the corner ribbing of heavy load carrying requirements. In this manner the sides of the case may be weakened by the provision of handle openings, with assured reliance upon the corner configurations for all vertical load carrying requirements.

More specifically, according to a preferred embodiment, each corner of the case is provided with plural vertical ribs as according to the later described arrangement, and a top load-supporting flange, the ribs, formed as outward deflections of the plastic stock, extending downwardly and outwardly at greater angularity than the case sides, and the top surface of the case flange being recessed to receive the ribs of a container stacked above, thus to assure load-transmitting alinement of the stacked ribs and an interlock against relative transverse shifting of the stack containers.

These features as well as additional details of an illustrative embodiment of the invention will be more fully understood from the following description of the accompanying drawings in which:

FIG. 1 is a view showing the case in perspective;

FIG. 2 is a plan view of the case;

FIG. 3 shows two stacked cases in side elevation;

FIG. 4 is a fragmentary enlarged section taken on line 44 of FIG. 3;

FIGS. 5 and 6 are enlarged cross sections taken through a lower case and bottom extent of an upper stacked case, respectively in the planes of lines 55 and 66 of FIG. 2;

FIG. 7 is a fragmentary enlarged plan view showing a corner of the case flange and its recessed relation with the ribs of an upper stacked case;

FIG. 8 shows in perspective another embodiment of the invention; and

FIG. 9 is a fragmentary illustration of the corner nesting relation of the FIG. 8 stacked containers.

ICE

Referring to the drawings, the case, thermoformed of plastic sheet stock, is shown to have essentially polygonal, in this instance, typically essentially square, generally curved corner shape. The sides 10 of the case are shown to be vertically planar and to have handle openings 11 at the inside of which tongues of the plastic are turned upwardly at 12 to form the handles proper. The top of the case is defined by a continuous outwardly projecting horizontal flange 13, the width of which may be increased somewhat at the corners 14 to accommodate the later described recesses. Starting below the flange as at locations 15, the plastic is deflected outwardly to form vertical ribs 16 and 17 extending at small downward and outward angularity, typically of about one-half degree for a case having a height of about 12 inches and approximately the the same transverse dimension between the side walls 10. As illustrated, the tops of the ribs merge into the upper smooth corner Walls of the case and have uniform outward deflection to its bottom 18. The bottom may be ribbed upwardly 19 to divide the bottom into four bottle resting areas.

Each rib 16 is located at the true corner of the case, with ribs 17 symmetrically spaced at each side of the center rib distances substantially as illustrated, assuring such rib distribution as will enable the ribs to assume at the corner extents of the case, as distinguished from the side area 10, at least the bulk of the load imposed by one or more superimposed stacked cases. Referring particularly to FIG. 2, each corner area 14 of the continuous flange 13 has recesses 20 and 21 corresponding in spacing and arrangement to the lower ends respectively of the ribs 16 and 17, so that in the FIG. 3 stacked alinement of the cases 22 and 23, the lower ends of the upper ribs 16a and 17a, will be received respectively within recesses 20 and 21 in the corner of the flange 13 below, resting upon the base surfaces 24 within the recesses formed by downward deflections 22a of the flange. FIG. 7 illustrates the interfit-ting relationship of the upper case ribs indicated by the broken lines at 16a and 17a, within the recesses 20 and 21. Thus the upper case ribs 16a and 17a are alined with the lower case ribs 16 and 17, and as a consequence, the vertical load transmission is from the upper to the lower alined ribs, largely independently of the side areas 10. Further, by reason of the interfitting relation of the ribs 16, 17 and the flange recesses 20, 21, the stacked containers are interlocked against transverse relative shifting, either linearly or rotationally.

FIGS. 8 and 9 illustrate a variational form of the invention similar to the described embodiment with respect to the corner rib configurations and their downward and outward angularities, but diifering in the top flange form and its interlock with a similar stacked case.

Here the case 26 is shown to have a top flange 27 having dropped corner extents 27a to form the stacked case interlock. The spacing of the bottoms of opposite outer planar surfaces 28 of the sides may be slightly less than the spacing of opposed inside surfaces 29 at the top so that the bottoms of surfaces 28 will nest inside surfaces 29, thus permitting the bottoms of the ribs 30 to rest upon the depressed surfaces 31 as shown in FIG. 9. Thus the nested relation of surfaces 28 and 29 prevent relative lateral shifting of the containers as does also the engageability of the outer ribs against the flange shoulders at 32.

In practical usage, the containers have been found capable of sustaining heavy stacked loads without consequential deformation, and to have shape retention throughout indefinitely extended usage.

We claim:

1. A plastic load carrying case of generally polygonal horizontal cross-section and having vertically extending sides below an outwardly projecting flange means at the top of the case, each corner of the case being formed with 3 vertically disposed ribs concave to the inside of the case through-out their length and commencing below the flange and extending to the bottom of the case at downward and .outwardtangularity relative to the case sides between the ribs, the top surface of said flange being downwardly recessed at the case corners to present a load bearing surface to receive the rib bottom of another corresponding case, said surface being greater in area than said rib bottoms whereby a pair of the cases may have stacked alinement and load transmission by way of the alined ribs.

2. A case according to claim 1, in which sides of the case between the corner ribs are essentially planar and have handle openings.

3. A case according to claim 1, in which each corner of the case has a central rib with similar ribs at each side thereof.

4. A case according to claim 2, in which said flange means is a' flange extending continuously about the case.

5. A case according to claim 4, in which said flange has top surface depressions at the corners of the case to receive the ribs of an upper stacked case.

6. A case according to claim 4, in which said flange at each corner of the case has plural recesses to individually receive the corresponding ribs ofan upper stacked case.

7. A case according to claim 5, in which the sides of the case are essentially planar and have handle openings, and formation of said ribs commence below said flange.

References Cited by the Examiner UNITED STATES PATENTS D. 169,743 6/1953 Fritz 220-97 2,760,676 8/ 1956 Knieriern 220-97 3,130,860 4/ 1964 Oberkircher 220-97 3,172,562 3/1965 Nascher 220-97 THERON E. CONDON, Primary Examiner.

GEORGE E. LOWRANCE, Examiner. 

1. A PLASTIC LOAD CARRYING CASE OF GENERALLY POLYGONAL HORIZONTAL CROSS-SECTION AND HAVING VERTICALLY EXTENDING SIDES BELOW AN OUTWARDLY PROJECTING FLANGE MEANS AT THE TOP OF THE CASE, EACH CORNER OF THE CASE BEING FORMED WITH VERTICALLY DISPOSED RIBS CONCAVE TO THE INSIDE OF THE CASE THROUGHOUT THEIR LENGTH AND COMMENCING BELOW THE FLANGE AND EXTENDING TO THE BOTTOM OF THE CASE AT DOWNWARD AND OUTWARD ANGULARITY RELATIVE TO THE CASE SIDES BETWEEN THE RIBS, THE TOP SURFACE OF SAID FLANGE BEING DOWNWARDLY RECESSED AT THE CASE CORNERS TO PRESENT A LOAD BEARING SURFACE TO RECEIVE THE RIB BOTTOM OF ANOTHER CORRESPONDING CASE, SAID SURFACE BEING GREATER IN AREA THAN SAID RIB BOTTOMS WHEREBY A PAIR OF THE CASES MAY HAVE STACKED ALINEMENT AND LOAD TRANSMISSION BY WAY OF THE ALINED RIBS. 